Search Results (183)

Microplastics are ubiquitous environmental particles with complex physical and chemical properties that enable them to interact with other contaminants. Recent evidence suggests that microplastics act as carriers for various chemical pollutants, altering their transport, deposition, and deposition dose. This conceptual review synthesizes current knowledge of radon progeny behavior and microplastic properties and suggests potential mechanisms for their interaction, although direct experimental validation of radon progeny specifically is currently lacking. It discusses attachment kinetics, transport pathways in air and water, and microplastic-mediated shifts in human lung deposition patterns and ecological exposure. Theoretical dosimetry reasoning suggests that, if attachment occurs, small respirable microplastics (1–10 μm) could increase inhalation doses by prolonging the airborne residence time of progeny indoors, whereas macro- and coarse microplastics would primarily affect localized environmental hotspots. These possibilities remain to be tested experimentally. Integrated experimental and modelling approaches, including radon chamber studies, aerosol and aquatic transport experiments, respiratory tract modelling, and ecological bioassays, are proposed to quantify these processes and inform risk assessment. Knowledge gaps remain in attachment efficiency, retention, co-contaminant interactions, and long-term exposure scenarios. Addressing these gaps is critical for refining human and ecological risk assessments and guiding regulatory frameworks in radon-microplastic-impacted environments. Full article

The increase in CO₂ concentration in the atmosphere can be attributed to various anthropogenic activities. Soils play a significant role in climate regulation, particularly through the storage of atmospheric carbon in soil organic matter. The main aim of the study was to examine the effects of site conditions on soil CO₂ flux in middle-aged stands of pedunculate oak (Quercus robur L.). A three-year study was conducted in three middle-aged stands within different subtypes of Chernozem. One of these stands is a windbreak (RŠ), while the other two stands (VN and DE) belong to larger forest complexes. Air samples were collected using the closed-chamber technique and analyzed using gas chromatography. The linear mixed-effects model (LMM) revealed that soil temperature, soil moisture, and location had significant effects on soil CO₂ flux (p < 0.05), whereas the effect of year was not significant (p > 0.05). The results showed that there was a higher temperature sensitivity of soil respiration (Q₁₀) in the windbreak (RŠ) compared to the other two stands (VN and DE). The mean annual carbon loss through soil respiration for all stands was assessed to be approximately 3.24 ± 0.12 t C ha⁻¹ yr⁻¹. These findings suggest that lower soil CO₂ flux in stands growing under optimal site conditions may indicate a more favorable carbon balance compared to stands growing outside their ecological optimum. Full article

Cropping systems and agronomic practices play a critical role in regulating soil organic matter dynamics and carbon dioxide (CO₂) emissions, which are key components of the global carbon cycle and climate change mitigation. However, the combined effects of tillage practices and seasonal climatic variability on CO₂ fluxes in chernozem soils (chernozems, WRB classification; highly fertile, humus-rich soils typical of steppe regions) of Northern Kazakhstan remain insufficiently understood. The aim of this study was to quantify soil CO₂ emissions under conventional tillage, no-till, and bare fallow systems during spring wheat cultivation on ordinary chernozems. Field experiments were conducted between 2023 and 2025 in the Kostanay Region (Kazakhstan). Soil CO₂ fluxes were measured using a chamber-based method, while soil temperature, moisture, and microbial community structure were monitored simultaneously. The results revealed pronounced seasonal and interannual variability in CO₂ emissions, ranging from 2 to 27 g CO₂·m⁻²·day⁻¹. Conventional tillage resulted in higher peak emissions due to increased soil aeration and accelerated organic matter mineralization, whereas no-till systems exhibited a more stable seasonal pattern and lower temperature sensitivity of soil respiration (Q₁₀ = 2.40 for no-till and 3.25 for conventional tillage). The application of machine learning techniques (Random Forest) significantly improved the prediction accuracy of CO₂ fluxes (R² = 0.67; RMSE = 3.37 g CO₂·m⁻²·day⁻¹) compared to linear models. These findings provide a scientific basis for the development of climate-smart agricultural practices aimed at improving carbon management in semi-arid steppe agroecosystems. Full article

Wildfires are key drivers of Mediterranean forest dynamics, yet post-fire recovery and carbon cycling in coastal dune systems remain poorly understood, particularly under invasive species pressure. This study quantified how microtopography and dominant woody species shape vegetation recovery, carbon stocks, and soil CO₂ efflux in a Pinus pinaster plantation burned in 2017 in coastal Portugal, during the fifth post-fire hydrological year (2021–2022). Vegetation composition, aboveground biomass, litter, soil organic matter and total organic carbon were measured across dune crests and slacks, and soil respiration was repeatedly assessed under native—Halimium halimifolium—and exotic invasive—Acacia longifolia—woody species using a closed-chamber system. Woody cover was higher on crests, whereas slacks supported greater herbaceous cover and stronger increases in soil organic matter, with litter dominating biomass and carbon pools in all microsites. A. longifolia showed marked demographic expansion and higher soil respiration than the native shrub, while mixed-effects models revealed non-linear, interacting effects of soil moisture and temperature on CO₂ efflux. Overall, post-fire recovery and carbon dynamics were spatially heterogeneous and increasingly controlled by invasion, underscoring the need for microsite-specific restoration and early invasive control to safeguard carbon sequestration and native forest resilience in Mediterranean coastal dunes. Full article

The continuous and reliable monitoring of soil organic carbon and soil respiration is vital for sustainable agricultural and environmental management. However, current manual methods are labor-intensive and time-consuming. This work focuses on the development of a fully automated robotic platform for in situ measurement of Soil Organic Carbon (SOC) and Soil Respiration (${\mathbf{R}}_s$). The system consists of a four-wheeled mobile platform, equipped with a robotic arm, and custom sampling and measurement tools. The platform is designed with a protected central opening that houses an on-board laboratory, enabling automated surface cleaning, soil drilling, sample collection and homogenization, SOC spectroscopy analysis, and chamber-based soil respiration measurement. The platform is equipped with a high-force mechanical insertion mechanism capable of operating a range of tools designed for soil treatment and penetration. These tools include a soil surface scraper, a soil respiration chamber, and a soil drilling unit. The mobile robotic laboratory system enables the sequential deployment of these tools in any desired order, providing flexible and efficient in-field operation. Full article

Assimilated carbon allocation to belowground processes may influence soil respiration (Rs). Because Rs includes autotrophic respiration (Ra) and heterotrophic respiration (Rh), different root and microbial responses complicate the separation of these effects. In a temperate deciduous broadleaf forest, we used sap flux density and estimated photosynthesis as indicators of plant activity. Total soil respiration and heterotrophic respiration were measured using automated chambers, and autotrophic respiration was estimated as Rs minus Rh. We examined the overall responses and time lags of respiration components. Ra showed positive relationships with sap flux density and estimated photosynthesis (R² = 0.37 and 0.30, p < 0.05), whereas Rh showed weaker relationships (R² = 0.20 and 0.15, p < 0.05). In lagged cross-correlation analyses using high-resolution data, Rs and Ra showed maximum responses 13 h after plant activity changes, whereas Rh showed no lag response (p > 0.05). These results suggest that associations with plant activity were clearer for Ra than Rh, and that the detected lagged response of soil respiration was more consistent with partitioned Ra than Rh. However, because Ra was estimated as Rs minus Rh, these patterns should be interpreted cautiously. Considering the responses and time lags of respiration components may improve ecosystem carbon cycling predictions. Full article

Accurate measurement of soil CO₂ flux is essential for understanding terrestrial carbon dynamics and quantifying greenhouse gas emissions from soil. However, the complexity and high cost of traditional measurement equipment limit its wide adoption in agriculture and other terrestrial ecosystems, including grasslands and managed field environments. In this paper, we developed a low-cost, automated soil CO₂ flux chamber for soil CO₂ flux monitoring. The flux chamber utilizes a commercially available MH-Z19 NDIR CO₂ sensor (Winsen Electronics Technology Co., Ltd., Zhengzhou, China), integrated with a Raspberry Pi microcontroller (Raspberry Pi Ltd., Cambridge, UK; manufactured by Sony UK Technology Centre, Pencoed, Wales, UK) for automated data collection and remote monitoring. The collected data are wirelessly transmitted to a computer or mobile device for real-time display. The total material cost of the system is less than $162. Side-by-side field measurements with a commercial LI-COR 8200-01S chamber (LI-COR Biosciences, Lincoln, NE, USA) showed that CO₂ fluxes measured by the low-cost chamber were consistently lower than those measured by the commercial instrument, averaging approximately 0.75–0.80 times the LI-COR values, indicating systematic underestimation in magnitude, while showing strong linear agreement (R² ≈ 0.98–0.99) across repeated field measurements. This indicates that the system reliably tracks relative changes in soil CO₂ flux, although a systematic bias in magnitude is present. This affordable and user-friendly chamber improves accessibility for researchers and field practitioners, enabling practical monitoring of soil CO₂ flux in applications where cost and portability are critical. Full article

Airborne particulate matter with a diameter of <10 μm (PM₁₀) can damage the corneal epithelium by inducing oxidative stress, disrupting the NRF2 antioxidant pathway, and triggering epithelial barrier dysfunction and inflammation. However, the role of mitochondria in mediating PM₁₀-induced damage remains unexplored. This study investigated the impact of PM₁₀ on mitochondrial homeostasis in both immortalized human corneal epithelial cells (HCE-2) and the mouse corneal epithelium, as well as the protective effects of SKQ1. For in vivo assessment, female C57BL/6 mice were exposed to either control air or PM₁₀ (±SKQ1) in a whole-body exposure chamber for 2 weeks (3 h/day, 5 days/week, with weekends off). In vitro, HCE-2 cells were exposed to 100 μg/mL PM₁₀ (±SKQ1) for 24 h, and mitochondrial function and morphology were evaluated. In vitro, PM₁₀ significantly impaired mitochondrial function by reducing basal, maximal, and ATP-linked respiration; reserve capacity; and coupling efficiency compared to the control and SKQ1 groups. PM₁₀ also downregulated mitofusin1 (MFN1) and optic atrophy1 (OPA1) and upregulated dynamin-related protein1 (DRP1) and mitochondrial fission protein1 (FIS1) in HCE-2 cells. In addition, PM₁₀ exposure significantly decreased the mitochondrial membrane potential; mitochondrial DNA copy number; and cytochrome c oxidase subunit 4 isoform 1 (COX4i1), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) levels. SKQ1 pre-treatment significantly attenuated these effects. In vivo, PM₁₀ exposure significantly decreased the levels of MFN1, TFAM, COX4i1, and superoxide dismutase (SOD2), whereas SKQ1 treatment significantly reversed these effects. Overall, these findings demonstrate that PM₁₀ exposure induces mitochondrial fragmentation, disrupts mitochondrial biogenesis and quality control, and reduces mitochondrial respiration, resulting in mitochondrial dysfunction. SKQ1 effectively reversed these changes, suggesting its potential as a therapeutic strategy to protect corneal epithelial cells from PM₁₀-induced mitochondrial damage. Full article

Gas exchange between soil or water surfaces and the atmosphere is one of the main sources of greenhouse gas production and absorption. Faced with global climate change and increasing atmospheric concentrations of these gases, significant scientific efforts are being made to monitor this exchange using various techniques, including closed-chambers. Although relatively simple, this technique requires careful attention to several key points. Furthermore, any installation using commercial chambers is relatively expensive. Indeed, given the specific variability of gas exchange, a single chamber cannot assess all the gas exchange in the soil of a given plot. Several chambers are therefore necessary, which increases the overall cost of the installation. In our laboratory, we have built different types of chambers: portable “nomad” ultra-low-cost chambers for punctual, large-area measurement campaigns and “automatic” cost-effective chambers for long-term installations. In this article, we aim to share our experience by describing our achievements and providing a link to the complete documentation, which includes 3D and 2D plans, Gerber files for manufacturing printed circuit boards, and a parts list. Full article

Background: Normobaric acute hypoxia models are widely applied to assess tolerance to acute hypoxic stress. Highland barley is a cereal crop originating from and traditionally cultivated in high-altitude regions; however, the dose–response relationship underlying its effects on hypoxia tolerance remains unclear. Methods: Male ICR mice were randomly allocated to five groups (n = 8 per group) and fed an AIN-93M basal diet or experimental diets supplemented with 20%, 40%, 60%, or 80% highland barley for 13 weeks. Hypoxia survival time was evaluated using a normobaric asphyxial hypoxia model, in which oxygen is progressively depleted in a sealed chamber by continuous respiration with carbon dioxide absorbed by soda lime. Hematological parameters, indices of oxidative stress and energy metabolism, and gut microbiota composition were also assessed. Results: Compared with the control group, dietary supplementation with 20% highland barley was associated with a longer hypoxia survival time (mean difference: 9.49 min; 95% CI: −2.05 to 21.02), whereas the 80% group exhibited the shortest survival time (approximately 40.6 min). In the 20% group, red blood cell count and hemoglobin concentration increased by 41.6% and 42.1%, respectively. ATP content and superoxide dismutase activity in brain tissue increased by 33.2% and 28.4%, respectively, with similar trends observed in heart tissue. In addition, gut microbiota α-diversity was increased in the 20% highland barley group, and distinct separation of microbial community structures was observed among groups receiving different supplementation levels. Conclusions: Overall, the data suggest that moderate dietary supplementation with highland barley (20%) is associated with a favorable physiological and microbiota profile under normobaric asphyxial hypoxic challenge, suggesting the presence of a potentially effective intake range for highland barley-based nutritional intervention. Full article

Non-contact monitoring of human vital signs using microwave radar has attracted increasing attention due to its capability to operate unobtrusively and through clothing or light obstacles. In vector network analyzer (VNA)-based radar systems, vital signs can be extracted from phase variations in the forward transmission coefficient $S_{21}$, whose sensitivity strongly depends on the electromagnetic performance of the antenna system. This work presents the design, optimization, fabrication, and experimental validation of a high-gain 12 GHz 4 × 4 microstrip patch antenna array specifically developed for phase-based vital signs monitoring. The antenna array was progressively optimized through coaxial feeding, slot-based impedance control, stepped transmission line matching, and mitered bends, achieving a simulated gain of 17.8 dBi, a measured gain of 17.06 dBi, a reflection coefficient of −26 dB at 12 GHz, and a total efficiency close to 74%. The antenna performance was experimentally validated in an anechoic chamber and subsequently integrated into a continuous-wave VNA-based radar system. Comparative measurements were conducted against a commercial biconical antenna, a single patch radiator, and an MIMO antenna under identical conditions. Results demonstrate that while respiration can be detected with moderate-gain antennas, reliable heartbeat detection requires high-gain, narrow-beam antennas to enhance phase sensitivity and suppress environmental clutter. The proposed array significantly improves pulse detectability in the (1–1.5) Hz band without relying on advanced signal processing. These findings highlight the critical role of antenna design in $S_{21}$-based biomedical radar systems and provide practical design guidelines for high-sensitivity non-contact vital signs monitoring. Full article

Tea (Camellia sinensis) cultivation is a major global industry that faces sustainability challenges due to soil degradation and greenhouse gas (GHG) emissions from intensive management. Biochar—charcoal designed and used as a soil amendment—has emerged as a potential tool to improve soil health, enhance carbon sequestration, and mitigate GHG fluxes in agroecosystems. However, field-scale evidence of its effects on GHG dynamics in woody crops like tea remains limited, particularly regarding methane (CH₄). Here, we present, to our knowledge, the first field assessment of biochar impacts on CO₂, CH₄, and H₂O vapour fluxes in a subtropical tea agroforestry system with and without shade trees in northeastern Bangladesh. Using a closed dynamic chamber and real-time gas analysis, we found that biochar application (at 7.5 t·ha⁻¹) significantly enhanced average soil methane (CH₄) uptake by 84%, while soil respiration (CO₂ efflux) rose modestly (+18%) and water-vapour fluxes showed a marginal increase. Canopy conditions modulated these effects: biochar strongly enhanced CH₄ uptake under both shaded and open canopies, whereas biochar effects on water-vapour flux were detectable only when biochar was combined with a shade-tree canopy. Structural equation modelling suggests that CH₄ flux was primarily governed by biochar-induced changes in soil pH, moisture, nutrient status, and temperature, while CO₂ and H₂O fluxes were shaped by organic matter availability, temperature, and phosphorus dynamics. These findings demonstrate that biochar can promote CH₄ uptake and alter soil carbon–water interactions during the dry season in tea plantation systems and support operational biochar use in combination with shade-tree agroforestry. Full article

The adoption of conservation systems in agriculture has been increasingly explored as a strategy to improve soil quality and potentially influence greenhouse gas (GHG) emissions. This study reports the first assessment of GHG emissions within a long-term (14 years) agroecological field experiment evaluating soil management systems for onion (Allium cepa L.) production in a Humic Dystrudept (Cambissolo Húmico Distrófico, Brazilian Soil Classification System) in Southern Brazil. Three management systems based on permanent soil cover and crop diversification were evaluated in an onion–maize rotation: conventional tillage (CT) without cover crops, no-till (NT) without cover crops, and a no-till vegetable system (NTV) with a summer cover crop mixture of pearl millet (Pennisetum americanum), velvet bean (Mucuna aterrima), and sunflower (Helianthus annuus). Short-term GHG emissions were monitored during one onion growing season (106 days), while soil chemical and physical properties reflect long-term management effects. Evaluations included (i) daily and cumulative GHG (N₂O, CH₄, and CO₂) emissions, (ii) soil carbon (C) and nitrogen (N) stocks, (iii) soil aggregation, porosity, and bulk density in different soil layers (0.00–0.05, 0.05–0.10, and 0.10–0.30 m), and (iv) onion yield and cover crop dry matter production. The NTV system improved soil physical and chemical quality and increased onion yield compared to NT and CT. However, higher cumulative N₂O emissions were observed in NTV, highlighting a short-term trade-off between increased N₂O emissions and long-term improvements in soil quality and crop productivity. All systems acted as methane sinks, with greater CH₄ uptake under NTV. Despite higher short-term emissions, the NTV system maintained a positive C balance due to long-term C accumulation in soil. Short-term greenhouse gas emissions were assessed during a single onion growing season, whereas soil carbon stocks reflect long-term management effects; CO₂ fluxes measured using static chambers represent ecosystem respiration rather than net ecosystem carbon balance. These results provide an initial baseline of GHG dynamics within a long-term agroecological system and support future multi-year assessments aimed at refining mitigation strategies in diversified vegetable production systems. Full article

Winter processes are increasingly recognised as important components of ecosystem carbon cycling, yet ¹³C-CO₂ fluxes from temperate forests and peatlands remain poorly quantified. This study quantified cold-season ¹³C-CO₂ fluxes in a Scots pine forest and a temperate fen in western Poland using manual closed chambers coupled with a Picarro G2201-i isotope analyser. Measurements were conducted during the cold half of the year and related to soil temperature, air temperature and, at the forest site, soil moisture. Median ¹³C-CO₂ fluxes were about twice as high in the forest (607 µg·m⁻²·h⁻¹) as in the fen (290 µg·m⁻²·h⁻¹), indicating stronger winter respiratory activity in the mineral soil than in the water-saturated peat. In the forest, ¹³C-CO₂ fluxes showed a weak, non-significant tendency to increase with temperature, whereas in the fen they were significantly negatively correlated with soil temperature and tended to peak near 0 °C, pointing to an important role of zero-curtain and freeze–thaw conditions. These plot-scale measurements provide rare constraints on winter ¹³C-CO₂ losses from temperate forest–peatland mosaics and highlight the need to represent cold-season isotopic fluxes in carbon–climate assessments. From a biogeochemical perspective, the findings emphasize that ¹³C losses during the cold season can occur as transient, high-intensity ‘hot moments’. Such episodic fluxes should therefore be explicitly incorporated into winter carbon accounting and isotopically enabled carbon–climate feedback assessments to improve the fidelity of annual net ecosystem exchange projections. Full article

This study is one of the first comprehensive assessments of soil carbon dynamics on the Black Sea coast of Russia, focusing on the role of soils in the terrestrial carbon cycle and the greenhouse gas balance of sub-Mediterranean ecosystems. Our integrated approach combined soil classification with the analysis of the distribution of organic and inorganic carbon, as well as the measurement of microbial biomass and respiration. Soil respiration components, including substrate-induced respiration (SIR) and basal respiration (BR), as well as greenhouse gas (carbon dioxide (CO₂) and methane (CH₄)) dynamics, were evaluated using a combination of laboratory and field measurements. Our results revealed significant differences between natural Rendzic Leptosols and terraced Skeletic Rendzic Leptosols (Technic and Transportic types). The latter contained higher organic carbon stocks (up to 25 kg m⁻²) associated with buried humus horizons, whereas the former were dominated by inorganic carbon accumulation. Microbial biomass carbon (MBC) ranged from 113 to 1119 µg C g⁻¹ of soil and decreased with depth. Basal respiration averaged 0.39 ± 0.30 µg C–CO₂ g⁻¹ h⁻¹. CO₂ emissions were strongly correlated with soil temperature (r = 0.65, p < 0.05) and negatively correlated with soil moisture, reflecting the predominant influence of abiotic factors. Seasonal chamber observations confirmed that these soils consistently function as CH₄ sinks, with negative CH₄ fluxes recorded across all seasons. Thus, Rendzic Leptosols on the Black Sea coast serve as significant CO₂ sources and stable CH₄ sinks simultaneously, and anthropogenic terracing enhances their potential for organic carbon sequestration. These findings refine our understanding of the carbon balance in sub-Mediterranean forest soils and highlight their dual role in greenhouse gas dynamics under changing climate conditions. Full article